What KSR did and did not change about the law of patent obviousness

In its landmark 2007 KSR v Teleflex decision, the Supreme Court rejected the rigid application of the “teaching, suggestion or motivation” test for patent obviousness, lowering the standards that infringers must meet to challenge the validity of patents. While KSR is recognized for bringing about a major shift in the law of obviousness, three aspects of the decision merit a more nuanced analysis. First, KSR did not abolish TSM, it simply held that TSM cannot be mechanistically applied to deny the existence of ordinary creativity and common sense. Second, contrary to some expressed beliefs, KSR did not make “obvious to try” a new obviousness standard; rather, it re-confirmed the principle that “obvious to try” alone is insufficient to show obviousness. Third, KSR expressed significant doubts as to whether the presumption of patent validity should apply when the obviousness prior art asserted in litigation was not previously considered by the patent office. This article explores those three aspects of KSR in further detail, and suggests ways in which patentees can continue to safeguard their interests in light of them.